The Mont Terri rock laboratory, a new international research project in a Mesozoic shale formation, in Switzerland

In many countries, argillaceous formations are being considered as potential host rocks for repositories of radioactive waste. Therefore, in 1995 several organisations decided to start an international research project in the reconnaissance gallery of the Mont Terri motorway tunnel, in north-western Switzerland, in a Mesozoic shale formation, the Opalinus Clay (Aalenian).

This project is under the patronage of the Swiss National Hydrological and Geological Survey. The following organisations are also partners in the project: ANDRA and IPSN (France), BGR (Germany), ENRESA (Spain), Nagra (Switzerland), JNC and Obayashi (Japan), SCKCEN (Belgium).

The aims of the project are to analyse the hydrogeological, geochemical and rock mechanical properties of an argillaceous formation, the changes of these properties induced by the excavation of galleries and to evaluate and improve appropriate investigation techniques. In January, 1996, eight niches were excavated for the project and 15 experiments were started in boreholes of no more than 30 m in length. In the winter of 1997–1998 a new research gallery was excavated to host further experiments. Different excavation, drilling and investigation techniques have been tested and improved. Significant results of the different experiments are already available. Some of those dealing with hydrochemistry, porewater pressure measurements and the evolution of the excavation disturbed zone (EDZ) are reported in this paper.     

河北邢台水位抬升现象的水化学成因分析

2018年9月以来,河北省邢台市出现了地下水位大幅回升、多口干涸泉眼复涌等宏观异常现象。为判定异常现象是否与区域内构造活动和地下应力改变有关,2019年4～6月进行了3期现场调查,并对3口灌溉井和6处地表水进行水样采集,分析了水化学离子浓度和氢氧稳定同位素等水化学数据。结果表明,3口灌溉井具有地表水的特征,补给来源相似且与地下水存在一定的水力联系;受区域煤矿资源丰富及人类活动的影响,水体中富含SO_4~(2-)离子。结合异常出现前的生态补水资料,分析认为2018年9月以来河北省邢台市水位抬升现象可能是由邢台地区生态补水引起的,与区域内构造活动和地下应力改变没有直接联系,排除其是地震宏观前兆的可能。     

六盘山地区泉水地球化学特征

根据六盘山地区泉水的化学组成和氢、 氧同位素数据, 讨论了该区地下水的化学类型、 成因及其动态变化特征。 2012年11月和2014年7月在六盘山地区采集10处泉水样品, 氢氧同位素由液态水同位素分析仪测定, 离子组分浓度由离子色谱和化学滴定法测定。 水样的TDS范围为218~27508 mg/L, δ¹⁸O和δD值分别为-12.0‰~ -8.5‰, -88.5‰ ~-61.3‰。 δ¹⁸O和δD指示该区泉水来源于大气降水, 并受水循环条件及水岩反应程度的影响。 根据舒卡列夫分类法, 所采水样可划分为10种水化学类型, 受含水层岩性控制, 宁南地区的水化类型主要为SO₄-Na型, 渭北西部地区的水化类型主要为HCO₃-Ca·Mg型。 两次所采水样的离子浓度显示多数水样点的HCO^-₃具有夏高冬低的季节性变化特征, 千川村(QC)、 双井村(SJ)等因含水层赋存环境较封闭, 受降水干扰小; 硝口村(XKH)泉水的离子毫克当量比值变幅最大, 说明该泉点水岩反应程度变化较大, 易受断层带活动的影响。 研究结果确定了六盘山地区水文地球化学背景和水的来源, 为该区流体地球化学地震监测、 预测提供了背景资料。     

青海可可西里东部盐湖水化学及沉积特征初步研究

2008 a夏对可可西里地区东部4个新发现的盐湖,进行了卤水水化学组分、矿物组成及其石盐元素含量分析。结果表明,该区水体卤水矿化度高,湖表卤水富硼锂等组分。通过对化学组分及水化学特征系数的研究,卤水的水化学类型主要为硫酸镁亚型和硫酸钠亚型。卤水pH值随着矿化度的增加而降低。Na+、Cl-含量与总矿化度呈正相关,SO42-"与矿化度呈负相关。Li与Mg物源、迁移规律近似。本区盐类沉积物以石盐为主,石盐中Si、Al、Fe、Sr含量低,其间相关性好,物质来源可能为周围岩石风化。布查盐湖盐类沉积存在少量硬石膏、半水石膏和铁白云石,表明布查盐湖的盐类物质来源很可能与地下热水作用有关。     

贵德盆地高氟、高砷地下热水分布及水化学特征

贵德县是青海省地方病危害最严重的地区之一。通过区域地质、构造及水文地质调查,表明:赋存于贵德群中的承压自流热水是当地饮水型氟中毒和砷中毒的致病水体;深度多小于400m,分布明显受控于NNW向压扭性断裂和NWW向张扭性断裂,并形成了两个异常中心。异常区围绕NEE向张扭性断裂带呈椭圆形展布,南北宽约5km,东西长约10km;其氟离子含量0.32～4.57mg/L,砷元素含量0.112～0.318mg/L,随深度和温度呈增高趋势;水温在16.0～45.9℃,pH较高,一般大于8.0,多属TDS0.2～0.5g/L的HCO3.SO4.C1—Na型淡水。为该地区防病改水提供了水文地质依据。     

水生植物对岩溶水化学日变化的影响——以桂林岩溶水文地质试验场为例

以桂林岩溶水文地质试验场为研究点,以研究水生植物对岩溶水化学日变化的影响为目的,着重研究水葫芦和水藻对岩溶水的pH、电导率、溶解氧含量、方解石饱和指数以及CO2 分压日变化的影响。试验结果表明: 在不同水生植物生长的岩溶水中,水化学的日动态变化规律是不同的。在水藻生长的水池出水口处,水的pH、电导、溶解氧含量、饱和指数以及CO2 分压所受的影响主要以水生植物的光合作用为主;而在有水葫芦生长的岩溶水中,水生植物的光合作用影响降低,而温度和根呼吸作用的影响增强。在以桂林岩溶水文地质试验场S31号泉水池出水口堰板处和堰板下游约3m 处为监测点试验时,试验结果表明其水生植物的影响占70%以上,强于温度作用的影响。      

柳林泉水化学特征及动态分析

柳林泉由100多个泉点组成,水质类型复杂、水温变化大。本文将其分为五个泉组,分别对各个泉组的水化学、水温及动态特征进行了分析,阐述了它们的分布规律及变化特征;对泉群流量的动态变化进行了相关分析、趋势分析和周期分析。结果表明: 自东向西,泉水水质逐渐变差,水温逐渐增高,泉水动态渐趋稳定。位于三川河南岸的泉点水温低,水质好;北岸的泉点水温高,水质差。泉流量的总体变化趋势呈指数曲线形式衰减,变化周期为16年,主要影响因素是降水入渗、河流渗漏及人工开采。      

A conceptual model for water resources circulation patterns in Andarokh-Kardeh region (NE,Iran)

Andarokh-Kardeh region is located northeast of Iran and provides notable part of potable water of Mashhad, the second most populated city of Iran with over 3 million inhabitants. Stable isotopes (¹⁸O, ²H and ¹³C), hydrodynamic, and hydrochemical indicators have been applied to evaluate water resources quality comprehensively and to present a hydrogeological conceptual model for the Andarokh-Kardeh region. Hydrochemical studies indicate that chemical rock weathering and ion exchange are the main factors controlling the quality of water in the region, while atmospheric (precipitation) as well as anthropogenic sources have no notable effect. Stable isotopes (¹⁸O and ²H) studies in surface and groundwater samples demonstrate enriched values in Kardeh Dam Reservoir (KDR) due to evaporation and also demonstrate that the interaction between KDR and downstream groundwater resources is negligible. The δ¹³C isotope and DIC and DOC concentrations indicate role of carbonate mineral dissolution from Mozdooran Formation, atmospheric and soil CO₂ and also the domination of C3 vegetation coverage in the study region. The developed conceptual model for Andarokh-Kardeh demonstrates different hydrogeological conditions during wet and dry periods, and highlights the main process which affect hydrogeology of the region. Water quality studies and the developed conceptual model demonstrate the main factors controlling water quality and the main hydrogeological characteristic of Andarokh-Kardeh region which can be used by water resources scientists for the future water management programmes.     

Temporal changes in leachate chemistry of a municipal solid waste landfill cell in Florida,USA

Evaluation of 12 years of landfill leachate chemical data from a lined cell of municipal waste in south Florida, USA shows an overall declining trend in major ion chemistry. The leachate is dominantly Cl, Na, HCO₃ and organic solutes. There are significant short-term variations in concentration that appear to be related to rainfall, rather than fundamental changes to leachate composition. Inorganic parameters related to pH, such as alkalinity, calcium, and magnesium appear to be chemically buffered. Chromium, cobalt, vanadium, zinc, and the metalloid boron display significant short-term co-variance with a decreasing trend. Iron and manganese concentrations increased significantly after capping. Based on the predominance of ammonia, historic methane generation, and increasing trends for iron and manganese after closure, the landfill cell has an anaerobic (reducing) interior environment. The reducing conditions were enhanced by capping and caused the most redox sensitive metals (manganese and iron) to become more mobile.     

艾比湖水化学特征的因子分析研究

采用最大方差正交旋转因子分析方法研究艾比湖水化学特征,结果表明,艾比湖水化学类型主要为硫酸钠亚型,盐湖湖水发育程度较深,Na+//SO42-,Cl--H2O是艾比湖的主要化学平衡体系等,这与艾比湖的实际情况完全相符。